Quotas in a Linux system are applicable at what level?

Quotas in a Linux system are primarily designed to limit the amount of disk space a user or a group of users can consume. While they can technically be applied in various contexts, the most effective and common usage is at the level of the entire device. When implementing disk quotas, the system administrator configures them on a filesystem basis, effectively allowing limits on the total amount of disk space and the number of inodes (files) that users can utilize across the entire device.

Setting quotas at the device level facilitates centralized management, ensuring that no single user can monopolize disk resources, leading to improved stability and performance of the system as a whole. This also helps prevent scenarios where users exceed their allocated space, which could potentially disrupt services and operations on that filesystem.

User-level quotas are often thought of as applying to individual users, but these are still managed within the broader context of the total space available on the device. Additionally, while you might manage directory-specific quotas using file attributes, these are generally not where the core functionality of quotas is implemented; the main management happens at the device level, where the total consumption for users is tracked across the filesystem as a whole.

Understanding how quotas operate at the device level is crucial for effectively managing resources on a